nodejs/lib/internal/test/transfer.js

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lib: add support for JSTransferable as a mixin Adds a new `makeTransferable()` utility that can construct a `JSTransferable` object that does not directly extend the `JSTransferable` JavaScript class. Because JavaScript does not support multiple inheritance, it is not possible (without help) to implement a class that extends both `JSTransferable` and, for instance, `EventTarget` without incurring a significant additional complexity and performance cost by making all `EventTarget` instances extend `JSTransferable`... That is, we *don't* want: ```js class EventTarget extends JSTransferable { ... } ``` The `makeTransferable()` allows us to create objects that are backed internally by `JSTransferable` without having to actually extend it by leveraging the magic of `Reflect.construct()`. ```js const { JSTransferable, kClone, kDeserialize, kConstructor, makeTransferable, } = require('internal/worker/js_transferable'); class E { constructor(b) { this.b = b; } } class F extends E { [kClone]() { /** ... **/ } [kDeserialize]() { /** ... **/ } static [kConstructor]() { return makeTransferable(F); } } const f = makeTransferable(F, 1); f instanceof F; // true f instanceof E; // true f instanceof JSTransferable; // false const mc = new MessageChannel(); mc.port1.onmessage = ({ data }) => { data instanceof F; // true data instanceof E; // true data instanceof JSTransferable; // false }; mc.port2.postMessage(f); // works! ``` The additional `internal/test/transfer.js` file is required for the test because successfully deserializing transferable classes requires that they be located in `lib/internal` for now. Signed-off-by: James M Snell <jasnell@gmail.com> PR-URL: https://github.com/nodejs/node/pull/38383 Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Khaidi Chu <i@2333.moe>
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'use strict';
const {
markTransferMode,
lib: add support for JSTransferable as a mixin Adds a new `makeTransferable()` utility that can construct a `JSTransferable` object that does not directly extend the `JSTransferable` JavaScript class. Because JavaScript does not support multiple inheritance, it is not possible (without help) to implement a class that extends both `JSTransferable` and, for instance, `EventTarget` without incurring a significant additional complexity and performance cost by making all `EventTarget` instances extend `JSTransferable`... That is, we *don't* want: ```js class EventTarget extends JSTransferable { ... } ``` The `makeTransferable()` allows us to create objects that are backed internally by `JSTransferable` without having to actually extend it by leveraging the magic of `Reflect.construct()`. ```js const { JSTransferable, kClone, kDeserialize, kConstructor, makeTransferable, } = require('internal/worker/js_transferable'); class E { constructor(b) { this.b = b; } } class F extends E { [kClone]() { /** ... **/ } [kDeserialize]() { /** ... **/ } static [kConstructor]() { return makeTransferable(F); } } const f = makeTransferable(F, 1); f instanceof F; // true f instanceof E; // true f instanceof JSTransferable; // false const mc = new MessageChannel(); mc.port1.onmessage = ({ data }) => { data instanceof F; // true data instanceof E; // true data instanceof JSTransferable; // false }; mc.port2.postMessage(f); // works! ``` The additional `internal/test/transfer.js` file is required for the test because successfully deserializing transferable classes requires that they be located in `lib/internal` for now. Signed-off-by: James M Snell <jasnell@gmail.com> PR-URL: https://github.com/nodejs/node/pull/38383 Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Khaidi Chu <i@2333.moe>
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kClone,
kDeserialize,
} = require('internal/worker/js_transferable');
process.emitWarning(
'These APIs are for internal testing only. Do not use them.',
'internal/test/transfer');
// Used as part of parallel/test-messaging-maketransferable.
// This has to exist within the lib/internal/ path in order
// for deserialization to work.
class E {
constructor(b) {
this.b = b;
}
}
class F extends E {
constructor(b) {
super(b);
markTransferMode(this, true, false);
lib: add support for JSTransferable as a mixin Adds a new `makeTransferable()` utility that can construct a `JSTransferable` object that does not directly extend the `JSTransferable` JavaScript class. Because JavaScript does not support multiple inheritance, it is not possible (without help) to implement a class that extends both `JSTransferable` and, for instance, `EventTarget` without incurring a significant additional complexity and performance cost by making all `EventTarget` instances extend `JSTransferable`... That is, we *don't* want: ```js class EventTarget extends JSTransferable { ... } ``` The `makeTransferable()` allows us to create objects that are backed internally by `JSTransferable` without having to actually extend it by leveraging the magic of `Reflect.construct()`. ```js const { JSTransferable, kClone, kDeserialize, kConstructor, makeTransferable, } = require('internal/worker/js_transferable'); class E { constructor(b) { this.b = b; } } class F extends E { [kClone]() { /** ... **/ } [kDeserialize]() { /** ... **/ } static [kConstructor]() { return makeTransferable(F); } } const f = makeTransferable(F, 1); f instanceof F; // true f instanceof E; // true f instanceof JSTransferable; // false const mc = new MessageChannel(); mc.port1.onmessage = ({ data }) => { data instanceof F; // true data instanceof E; // true data instanceof JSTransferable; // false }; mc.port2.postMessage(f); // works! ``` The additional `internal/test/transfer.js` file is required for the test because successfully deserializing transferable classes requires that they be located in `lib/internal` for now. Signed-off-by: James M Snell <jasnell@gmail.com> PR-URL: https://github.com/nodejs/node/pull/38383 Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Khaidi Chu <i@2333.moe>
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}
[kClone]() {
return {
data: { b: this.b },
deserializeInfo: 'internal/test/transfer:F',
lib: add support for JSTransferable as a mixin Adds a new `makeTransferable()` utility that can construct a `JSTransferable` object that does not directly extend the `JSTransferable` JavaScript class. Because JavaScript does not support multiple inheritance, it is not possible (without help) to implement a class that extends both `JSTransferable` and, for instance, `EventTarget` without incurring a significant additional complexity and performance cost by making all `EventTarget` instances extend `JSTransferable`... That is, we *don't* want: ```js class EventTarget extends JSTransferable { ... } ``` The `makeTransferable()` allows us to create objects that are backed internally by `JSTransferable` without having to actually extend it by leveraging the magic of `Reflect.construct()`. ```js const { JSTransferable, kClone, kDeserialize, kConstructor, makeTransferable, } = require('internal/worker/js_transferable'); class E { constructor(b) { this.b = b; } } class F extends E { [kClone]() { /** ... **/ } [kDeserialize]() { /** ... **/ } static [kConstructor]() { return makeTransferable(F); } } const f = makeTransferable(F, 1); f instanceof F; // true f instanceof E; // true f instanceof JSTransferable; // false const mc = new MessageChannel(); mc.port1.onmessage = ({ data }) => { data instanceof F; // true data instanceof E; // true data instanceof JSTransferable; // false }; mc.port2.postMessage(f); // works! ``` The additional `internal/test/transfer.js` file is required for the test because successfully deserializing transferable classes requires that they be located in `lib/internal` for now. Signed-off-by: James M Snell <jasnell@gmail.com> PR-URL: https://github.com/nodejs/node/pull/38383 Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Khaidi Chu <i@2333.moe>
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};
}
[kDeserialize]({ b }) {
this.b = b;
}
}
module.exports = { E, F };